A groundbreaking study demonstrates that the type of surroundings a mouse lives in can impact the state of their immune system. An “enriched” environment significantly bolsters their infection-fighting abilities.

Interactions between psychological wellbeing and the immune system slowly strengthen.

Without the immune system, animals would be open to a myriad of microbial invaders.

As such, research into the vast, interconnected pathways of the immune system is vital.

Over recent years, researchers have deepened our understanding of the factors that influence the strength of our immune response.

For instance, factors such as environmental pollution, location, social status, and psychological state have all been found to play a part in autoimmune disorders – conditions where the body attacks its own healthy cells.

New lines of scientific inquiry are beginning to unlock the effects of our mental state on our immune system.

Researchers from Queen Mary University of London in the United Kingdom, led by Prof. Fulvio D’Acquisto, set up an experiment to investigate the role that environment plays in the immune response of mice.

The findings, published in Frontiers in Immunology, are the first to demonstrate that an enriched environment can influence the function of T cells.

T cells have a myriad of vital roles in the immune system, including scanning our bodies for invaders and directly destroying them; they also play a part in rheumatoid arthritis and HIV, among other diseases.

Changing a mouse’s environment

The researchers put mice into either normal or “enriched” environments for 2 weeks. The standard cages consisted of nesting material and sawdust. The enriched cages (below) were a more elaborate affair, providing a “multisensorial” living space; this included a wider cage, wood shavings, a colored nest-box, fabric tube, running wheel, and a swing.

Enhanced mouse environment.Image credit: Queen Mary University of London

At the end of the 2-week period, T cells were taken from the mice and presented with an agent that mimics an infection.

When the immune responses of the two groups of mice were compared, there were some striking differences.

The mice from the enriched cages were found to produce higher levels of interleukin 10 and 17, hallmarks of a robust immune response; in other words, their T cells were boosted making them more ready to mount a proactive inflammatory response.

In all, the enriched environment mice showed an increase in 56 immune-specific genes, many of which are known to be involved in fighting infections and promote healing.

Prof. D’Acquisto was impressed by the changes. Just 2 weeks spent in the enhanced surroundings changed the mice’s immune systems; they were “completely different and seemed to be better prepared for fighting infections,” he said.

The changes surprised the team because no drugs were needed to give the mice this significant change in immune response – just simple changes in their living conditions.

Although the current research only investigated one cell type and was carried out using healthy mice, the results are tantalizing.

Of course, the findings will need to be replicated in humans, but if they are, it could be a game-changer for the future of healthcare. It may be possible to boost the effectiveness of current pharmaceutical treatments by altering environmental conditions.

An interview with Prof. D’Acquisto

Medical News Today recently caught up with Prof. D’Acquisto and delved into the details of this fascinating immune-environment interaction.

MNT: Do you have any theories as to why these environment-mediated immune changes might have evolved?

Prof. D’Acquisto: “The immune system is the ‘language’ that the body uses to gain information about its surroundings. Through the immune response, we learn if other organisms (bacteria, viruses, etc.) or certain conditions (stress, relaxation, etc.) are suitable and conducive to our existence or survival.

Given the huge variety of organisms and conditions that living beings encounter during their lifespan, there has been a need for the body to develop a system that can dynamically respond to all these challenges and information. This is one of the main reasons why we nowadays consider the immune system as ‘plastic,’ i.e., always changing, always adapting to the external environment.

This is rather interesting in my opinion, considering that the immune system is the only tissue apart from the nervous system that has the capacity to remember its experiences (what we call immunological memory). This concept poses the question as to whether we can also ‘immunologically memorize’ positive and negative life events, such as marriage or the death of the loved one.”

An example of a standard non-enhanced mouse cage.Image credit: Queen Mary University of London

MNT: The findings are fascinating and, although we will have to wait for them to be replicated in humans, the potential changes to healthcare could be enormous in the far future.

Do you think that further down the line, people might be prescribed holidays rather than drugs? Could we see the start of health service-funded holiday camps?

Prof. D’Acquisto: “I am not sure I would go that far! Holidays can be relaxing and pleasant for some people and stressful for others.

I think that the most important aspect of our study is the concept that changing our living conditions, even for as little as 2 weeks (of a mouse life), can have a significant impact on our immune system.

These changes can influence the way drugs works and help therapies become effective.

In an ideal world, patients should be asked: ‘when was the last time you felt fit and healthy? When did you last have a laugh or a good time? What could you do to go back to this time?’

We are all different, and we all have different needs, desires, and aspirations. Incorporating these aspects into a therapeutic treatment is, I believe, the first step toward the most wanted ‘personalized treatment.’

In the context of immune diseases, I always say that ‘the immune system is the mirror of our emotional well-being.’ Therefore, anything that can change the emotional state of patients suffering immune diseases can potentially have a huge impact on their physical state.”

MNT: Do you have any further research in this field planned?

Prof. D’Acquisto: “We are continuing to develop this field of research, that I have called affective immunology, from different perspectives. In our previous study, we assessed the impact of massage and caressing on the immune system and discovered a very interesting link between the sense of touch and the number of immune cells we have in our blood. This is another way we can modulate emotions and improve the immune response.

We are currently investigating how to use all this information to improve patient care as well as maintain a healthy status of well-being. As an example, we have been testing ‘beds for mice’ that are made with textiles that can be pleasant to touch and hence make the immune system work better (immunostimulatory textiles). This would significantly shorten the duration of disease and save the NHS [National Health Service, U.K.] some money.”

MNT: In a perfect world, with unlimited funds and time, what study would you like to run?

Prof. D’Acquisto: “I would like to have funding to involve the public in my research. We are currently investigating if positive and negative emotions use the same mechanism to influence the immune response, or if there are separate ways this happens.

In other words, we are wondering if there is a single switch that can be turned high or low to have ‘high and low’ emotional states, or if we have two separate switches for it. This is all being done in mice, and I would like to verify this in human volunteers that consider themselves in high or low emotional states.

I would like to hear their stories and see if there is anything that can be learned from it.

Understanding how this crosstalk between emotions and immunity works will ultimately help us provide better treatment for patients. One could indeed foresee using the same treatment we currently have just ‘supplemented’ with ’emotional modulators.'”

Read more about the interaction between the brain and the immune system.